@Anonymous User
Welcome to the forum. If you've changed the router password from the default and forgotten it then unfortunately the only way to get in is to factory reset the hub, this will change everything back to default settings s if you've made custom changes to the hub you'd have to set those all back up again. To do this press the reset button on the back for about 10-15 seconds until you see the power light flash a few times.
PS If you mean you need to add a new device to your NOW TV list to watch NOW TV you don't need to do anything at the hub for this, devices are added to your NOW TV list by logging into the NOW TV app and starting to watch something on your pass.